Telephone-call circuits



J. F. TOOMEY AND 0. H. LOYNES.

.TELEPHONE CALL cmculsl APPLICATION FILED APR. 21.1920.

Patented Sept. 5, 1922- -1 unam. mvcsu numcga 2 unan/.anc sg Nenn/vean ATToRNEY Sept.. 5, 1922..

JOHN F. TOOlVFY, NEW YORK, N. Y., AND Ovt/'EN H. LOYNES, QF 1VO0D RIDGE, NEW JERSEY, .ASSIGITORS T0 .AMEBXCAN`TELEEHONE ANZI) TELEGRAE'H COMPANY, A

oonroen'rron or New Yoan.

TELEPHONE-CALL CIRCUITS.

Application filed April 21,

To all fr0/,7mm 'it may concern.' v

Be it known that we, lor-IN F. Tooiuinr and OWEN H. LovNns, residing at New York and Wood Ridge, inthe counties of New York and Bergen, and States of New York and New Jersey, respectively, have invented certain improvements in rlelephone-Call Circuits, of which the following is a'specitlcation.

This invention relates `to telephone circuits, and lmore particularly to telephone call wire circuits. In practice when a subscriber wishes to be connected with another subscribed, the number of the wanted subscriber is communicated to an operator at a central. oilice and it the called subscriber is connected with that particular oiiice the call maybe completed thercat. it, however the line ot the desired subscriber is lconnected to a distant ottico, it is necessary that a conductor, commonly known as a 'trunk line, shall be provided between the two ofices with which the lines of both subscribers may be connected. it is also necessaryto provide means whereby the opera-tor at the central oiiice shall be enabled to communicate time.

with an operator stationed at a distant oilice in order that the distant operator may assign to the central oiiice operator the particular trunk line to be used 'for the conncction. For this purpose ateach initiating operators position there are provided cer,- tain keys or buttons which enable the operator to complete a talking circuit to a distant orifice. These are ordinarily -termed call wire circuits. 1n previous kcall -wire systems, the circuits were so arranged 'that either one or all the o'ierators in the same oilice could bridge their telephone sets across the call wire circuits at the same This 'feature caused considerable trouble because the connection ot a large number oi: operators sets to the call lwire circuit'- at the same time reduced the transmission eliicicncy to ay point where it was di'iiicult to pass calls over the circuit. Accordingly, one of the principal objects ot this invention consists in the provision oi means whereby a call circuit is adapted to be used by vonly a predetermined number of operators at a time, the circuit being inoperative at suchinterval to other operators. Another feature consists in providing fsig` 1920. Serial No. 375,568.

tions that the wire circuit is inaccessible tor connection at this time. Other and further eaturesof theinvention will hereinafter appear.

. This invention may now be more fully understood by reference to the accompanying drawing, in which three embodiments are diagrammatioally. illustrated.r

In the arrangements of the invention there are shown in Figuresl, 2 and 3 four telephone switchboard positions, A, A1., A2 and A3, together withl the essential elements pertaining` to the improved circuits. While only` fourpositions are illustrated, itwill be understood that many additional positions may be associated therewith. At each position there are aplurality of call circuit keys or buttons,1one oit said keys'be ing illustrated at `each of the above ment-ionedypositions as indicated by the numerals 1, 2, 3 and 4. .i Associated with each oit said keys is a positionk relay as showny at 5, 6, 7 and 8. These relays are arrangedk tively, with the relays 5, 6, 7 and 8.y Said relays when operated connect the operatorie talking set with the call circuit 2O.,`

ln 'F 1 a lowl resistance relay 21 is shown as connected in common with. the position relays 5, 6, 7 and 8. Upon the depression of any one call cir-cuit key, the relay 21 is removed from fthe control of the remaining keys,thereby allowing only one operator access to thecall circuit at one time. The energization of relay`v21 clauses the operation oit relay 22, and the latter relay, upon operating, closes acircuitr which provides for the yillumination of the lamps at all 'other positions except the one at' the position where the key is actuated.

ln Figs. 2i and 3 are illustrated modifica-k tions oi Fig. 1. Fig. 2 isarranged so that two operators mayk have access to the call circuit at one time, while Fig. 3 is arranged for the accommodation of three operators. A low resistance relay 23, is connected in common with the call circuit lreys in. a manner similar to relay '2l in Fig. l. Diterential relays 2li and 25 have one of their windings connected in series with relay 23 and the operation of the latter relay will close a circuit by way of its armature through the opposite windings o'f said diterential relays. Resistance elements 26 and 27 oi kdifferent values are associated, respectively, with the differential relays 2l and 25q and these resistances serre to provide a balanced or unbalanced condition of said dillerential relays, according to the number of call circuit keys operated one time. ln Fig. 2 the relay/s 2i and 25 will become unbalanced upon the depression of two call circuit lreys at one time, and in Fig. 3 said relays will be unbalanced upon the actuation of three call circuit lreys. rllhe operation of both differential relays will cause relay 28 to be energized, thereby preventing additional connection with the call circuit at such time. rlhe operation of relay 28 will also close a circuit whereby the lamps atall other positions except those in use are illuminated.

The details oi' these circuits may be more suliiciently understood from the following description ot their operation.

ln Fig. l, which is designed for the use of but one operator at a time, an operator, for instance, at position A desiring to communicate with a distant oi'lice depresses the call circuit key l, thereby closing a circuit from battery, winding of relay 2l, conductor 29, winding of relay 5, contact 30, righthand contact of lrey l, conductor 3l, armature of relay 2l to ground. The closing of this circuit causes the energization of relays 5 and 2l. rllhe operation of relay 5 opens the contact at 30 and closes a locking circuit from ground, lett-hand contact ot key l, contact 32 and winding of relay 5, conductor 29, winding of relay 21 to battery. Relay 5 is thus maintained energized while key l is operated, and while said relay is .in an operated condition, a circuit will be closed through its right-hand contacts ttor the connection of conductors lo which lead to an operators telephone set, thereby providing for connection with the call circuit 20. rllhe operation of relay 5 also breaks the ground connection at its outer left-hand Contact, thereby preventing lamp l() 'from lighting at this time. The operation ,of relay 21 closes a circuit by way of its front contact from ground, winding of relay 22 to battery. This circuit causes the relay 22 to operate and closesthe following circuit: From battery, contact 33, coinnion yconductor 14 through the lamp iilainents et each of the associated positions to ground,

thereby lighting the lamps at all unactuated positions. rlhis condition prevails until the operator at A restores her lrey to normal. Should an operator ignore the busy signal as indicated by the lighting of the position lamp, and attempt to obtainconnection with the call circuit, she will be unable to do so because the normal ground connection through contact 34 of relay 2l was opened upon the energization or" relay 21. Thus an exclusive connection with the call circuit of only one position at a time is assured.

The depression ot an initial. key in Fig. 2, such lor example as key l, will close a circuit from grounded contact /l-l oft relay 2S, conductor 55, right-hand contact of lrey l, normal contact 80, winding ot relay 5, conductor 3G, winding ot relay left-hand windings oit` differential relays 24- and 25 to battery. rlChis circuit will energize relays 5 and 23. 'l he ope ation oi relay 5 will connect the operators set with the call circuit through its right-hand contacts, and will also break the normal ground connection at its outer lett-hand armature and prevent the illumination of the associated sional lamp l() in a manner similar to that dfV .".hed in connection with the operation or said relay in Fig. l. The operation of relay 5 will break the circuit through contact 30 and close a locking circuit `trom ground, letthand contact or key l, inner left-hand contact and windingof relay 5 and over conductor 3G previously outlined whereby relay 22? was energized. The operation ol relay 23 closes a circuit over its grounded contact to point 37. where the circuit divides into two branches.r one branch passing through resistance 26 and right-hand winding oll dillfereutial relay 2i to battery, and the other branch through resistance 27 and right-hand win-ding ot differential relay 25 to battery. The circuits previously tracedv which pass through the windings of differential relay 2li are oit different resistance values and provide an unbalanced condition ci? said relay and cause it to operate, but its operation at this time, however, provides no use'lul function. At the same time the circuits traced through the windings of differential relay 25 are oi1 equal resistance and prevent said relay Vtrom operating. The operation ol :i second call key. ilor instance. rey 3 at position A2. at this time will close a circuit from grounded contact 4l. of relay 28, conductors 35 and 38, right-hand contact orf lrey 3, contact 39, winding` of relay 7, conductors 40, 9 and 36, winding oit' relay 23 and right-hand windings of differential relays 24 and 25 to battery. `The closingof this circuit will operate relay 7 causing said relay to connect the telephone set at position A? with call circuit 2O in an obvious manner. The operation of relay 7 will break` the normal ground connection at its outer left-hand contact and also thecontact at 39 in a manner similar to that described in connection with the actuation of key 1. The breaking of contact 39 will open the circuit through right-hand contact of key 3 previously described and close a circuit from ground,`lefthand contact of key 3, inner left-hand contact and winding of relay /7, over conductors 4K0, 9 and 36, winding of relay 23 and left-hand windings of differential relays 24 and 25. The closing of this circuit will maintain relays 23 and 24 energized but the resistance values now included in said circuit will change the balanced condition previously existing 'between the windings ofdiiferential relay 25 to a condition of imbalance thereby causing said relay to operate. The operation of relay 25 will close a circuit from the ground, contacts of relays 25 and 24, winding rof relay 28 to battery. The closing of this circuit will cause the energization of relay 28, which upon operating will attract its armatures opening the ground connection at its right-hand contact 41 and closing through left-hand contact 42 a circuit from battery, common conductor 14 to ground through the filaments of lamps 11 and 13.V

The lamps 5 and 7 at positions A and .A2, respectively, will not light at this time for the reasons previous explained. Thus when any two operatorsv are connected with the call circuit. as yshown in Fig. 2, a `ousy signal lamp will light at all other positions, and the operators thereat are prevented from conneet-ing with said call circuit at such time,y

In case the busy indication is disregarded and a key is depressed the position relay associated with said key will not operate because a circuit cannot be closed at this time due to the open contact 41 of relay 28. lf one operator disconnects from the call circuit while the other operator remains connected therewith, the busy lamps at all the positions will go out and the same conditions will prevailV as pointed out in connection with the operation ofkey 1 at position A,

and a second operator may then be permitted access to thecall circuit.

The modiicatiou, as shown in Fig. 3, is similar to F but permitsthe connection of three operators with the call circuit at a time, The depression of an initial key 1 at position A will cause the same circuit operation as described in connection with said key in Fig. 2, and provide for the energization of relays 5, 23 and 24. The actuation of a second key will also cause the same cir;

.cuit conditions to prevail as explained in connection with key 3 at position A2. ln this instance, however, the resistance values included in the circuit will be suoli as to balance the windings of relay 24 causing said relay to become deenergized while the windings of relay 25 will be an unbalanced condition `causing it to become energized. The energization or deenergization of said relays at this time, however, will perform no useful function.v The operation of a third key, for instance, key 4- atA position A3 during the' interval the keys 1 and 3 at positions A and A2, respectively, are actuated will close the 'following parallel circuit: fromground, contact 41 of relay28, conductors 35 and 38, right-hand contact of key 4l, normal contact of position relay 8, winding of relay 8, conductors9 and 36, windingof rela-y 23 and left-hand windings of relays 24 and 25 to battery. The closing of this circuit will energize relay 8 and said relay upon operating will perform the same functions as outlined in connection with the previously mentioned position relays. The effective parallel resistance included in the circuit by the operation of relay 8 is such as to cause a condition of imbalance in the windings of both differential relays 24 and 25, thereby causing them to operate and close a circuit from ground through their contacts, winding of relay 28 to battery. This circuit will energize relay 28 which upon operating will attract its armatures breaking the contact at lll, and closing a circuit by way of its righthand contact 42 which will cause the lamps to light at all positions other than those where the keys are depressed, as previously explained. When any one or two of the operators release a call circuit key,`the circuit will resume the condition previously described in connection with the depression of two or one keys thereby rendering said call circuit accessible for the lconnect-ion of three operators at all times. ln a manner similar to that explained in connection with Fig. 2 the breaking of contact 41 will prevent additional connection of other positions at such times. 4 f

While resistances of certain values are herein employed byway of illustration, it will be understood that resistances or other values may be used. It will also be obvious that the-general principles herein disclosed may be embodied in many other organizations widely different fromthose illustrated without departing from the spirit of the invention as deiined in the followingclaims.

kVifhat is claimed is: f I

1. In a telephone system comprising a plurality of switchboard positions, a call circuit common to said positions, a key at each position, a relay for each position associatedwith each key, a signal associated with each relay, the relay for any position being operable upon the depression of the key at said position to provide a connection with said call circuit for that positionand to render its asso-- ciated signal inoperative, and means responsive to the'actuation of a number less than the total number of said relays for prevent- CIJ ing the actua-tion of the remaining relays and operating the signals associated therewith.

2. iii. telephone system comprising a plurality oi switchboard positions, a call circuit coinnion to said positions, a key at each position, a relay 'for each position associated with each key, the relay tor any position being operable upon the depression of the key at said position to provide a connect-ion with said call circuit ttor that position, and means reslionsive to the actuation oi? number of relays greater than one for preventing the actuation oil the remaining relays.

Si. i". teleplioncsysteni i-oinprising a plurality v switchboard positions, a call circuit common to `said positions, a key at each position, a relay foreach position associated with each key, the relay for any position being operable upon the depression of the key at said position to provide a connection with said call circuit for that position, a signal associated with each relay, means responsive to the actuation or" a number of relays greater than one for preventingl the actuation of the remaining` relays, and means tor operating the signals at all unactuated relay positions.

4r. A telephone system comprising a plurality of switchboard positions, a call circuit common to said positions, a key for each position, a relay for each position associated with each key, the relay 'for any position being operable upon the depression oi the key at said positions to provide a connection with said call circuit for that position, and means responsive tothe actuation of more than two relays to prevent the actuation of the remaining relays.

ln a telephone system coinprisino a plurality or' switchboard positions, a call circuit common to said positions, a key for each position a relay for each position associated with each key, the relay for any po sition being operable upon the depression of the key at said position to provide a connection with said call circuit for that position, a signal associated with eachrelay, means responsive to the operation of more than two relays to prevent the actuation of remaining relays, and means i'or operating the signals at all unactuated relay positions.

6. In a telephone system comprising a plurality orn switchboard positions, a call circuit common to said positions, a key asso# ciated with each position, means operable upon depression of the key at any of said positions for connecting that position with said call circuit, means responsive to the operation of a plurality of said keys less than all thereof for preventing additional connection of positions associated with the remaining keys to said call circuit.

'7. ln a telephone systein comprising a plurality ot kswitchboard positions, a call circuit common to said positions, a key associated with each position, a relay associated with each key, operable upon depression of the key for connecting that position with said call circuit, a signal associated with cach relay and rendered inoperative upon the Aactuation thereof, means responsive to the operation of a plurality ot said keys less than all thereof for preventing additional connection ot positions associated with the remaining keys to said call circuit, and means for operating the signals at all positions not associated with said call circuit.

8. In a telephone syste-in comprising a plurality of switchboard positions, a call circuit coinmon to said positions, a key associated with each position, a relay operable upon the depression of a key at any of said positions for connecting that position with said call circuit, a signal associated with each relay, diliierential relays serially7 connected with said rst relay responsive to the opera-tion of a. plurality of keys less than all thereof for preventing additional connection of positions associated with the remaining keys to said call circuit, and a relay responsive to the operation of said difierential relays tor operating the signals at all positions not associated 'with said call circuit.

9. ln a telephone system comprising a plurality or switchboard positions, a lcall circuit common to said positions, a key associated with each position, a position relay operable upon the depression of a key at any ot said positions tor connecting that position with said call circuit, a signal associated with each position relay and in parallel relation with respect to each other, differential relays serially connected with said irst relay responsive to the operation of more than two position relays for preventing the actuation ot the remaining position relays, and means responsive to the operation of said differential relays for operating the signals at all unactuatcd position relays.

In testimony whereof, we have signed our names to this specification this 19th day of April 1920.

JOHN F. TOOMEY. t OWEN H. LOYNES. 

